CCS has various disadvantages: the infrastructure is expensive to build; the separation and compression of the CO2 takes large amounts of energy; and there will always be a small risk of leakage from storage sites. Nonetheless, with so many existing and planned coal-fired power stations in the world, a growing number of experts believe that only with the help of CCS will it be possible to reduce global greenhouse emissions to a safe level.

In Manchester, Staffan Gortz, made the case for CCS on behalf of Vattenfall, the Swedish energy giant that has built a pioneering carbon-capture power station in Schwarze Pumpe, Germany. This pilot-scale plant uses the so-called oxyfuel approach to capturing carbon. Nitrogen is removed from the air, enabling the fuel to burn in pure oxygen. This results in a waste stream of virtually pure CO2, ready for capture and storage. Vattenfall and other companies are also investigating two other CCS technologies, known as pre-combustion and post-combustion.

Perhaps the most exciting element of CCS is the prospect of "carbon negative" power plants. These would work by co-firing (burning a mixture of) wood and coal. Since wood is partly made of carbon pulled from the air by growing trees, a CCS power station fuelled by a mixture of coal and sustainably harvested wood could actually reduce the amount of greenhouse gas in the air.